The purpose of the research is to relate the previously described intracellular behavior of certain fungi within phagocytes to their sensitivity to identifiable antifungal substances derived from such cells. The purpose is to be achieved by the following comparative studies: 1. Studies with Histoplasma capsulatum: a. The comparative effect of oxidative and non-oxidative antifungal systems from PMN on conidiospores and blastospores of the fungus. b. Studies on the cationic proteins derived from circulating and cultured monocytes; from caseinate and glycogen induced macrophages; from immunized and normal animals; and from alveolar and peritoneal macrophages. 2. Studies with Torulopsis glabrata and Candida pseudotropicalis. A study of non-oxidative antifungal systems from the peritoneal cavity of normal animals.